GeoForensic Project

The All-American Canal

OVERVIEW

The IID All American Canal Repair project involved working with the Bureau’s Technical Committee
from Denver to evaluate distress incurred namely by the All American Canal and its siphon
crossing at New River – as well as other large facilities. This area was particularly hard hit
by high ground acceleration, and suffered significant liquefaction and other damage as a result
of the Easter 2010 M7.2 Laguna Salada Earthquake event. Ultimately, our work included a
large-scale evaluation and background review to determine the character of the embankments, the
characteristics of the alluvium and lacustrine deposits that underlay and support the canal, and
the siphon features.

Larry Fanning, G3Soilworks’ President and technical director, served as the lead engineering,
geologic, and geotechnical advisor, as well as point man for SoilWorks, per request of IID. He
assisted IID and the Bureau of Reclamation in the evaluation, and ultimate repair, of large
water conveyance features in Imperial Valley that are operated by IID for the Bureau.

Larry utilized the G3 method, as he employed a variety of surface and subsurface investigation in
the assessment to evaluate the distress that developed as a result of high ground accelerations
and liquefaction and lateral spreading effects.

Key Project Notes

Worked with US Bureau of Reclamation, Imperial Irrigation District, County, and Cal-EMA
officials to quickly but effectively assess damages and both temporary and permanent repair;

Performed slope stability analysis and other studies of as-damaged conditions;

Monitoring well and Flow net analysis of groundwater and seepage;

Downhole direct examination of the embankment materials;

Special methods and uses of geophysical methods to investigate system integrity;

Instrumentation to look at the influence and effects of liquefaction and lateral spreading
evident along the embankment toe of slopes.